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Page 1786, results 44626 - 44650

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Publication Extents

Not all publications have extents, not all extents are completely accurate
Geohydrology and ground-water resources of Philadelphia, Pennsylvania
Gary N. Paulachok
1991, Water Supply Paper 2346
The aquifers underlying the 134.6-square-mile city of Philadelphia are divided by the Fall Line into the unconsolidated aquifers (chiefly sand and gravel) of the Coastal Plain and the consolidated-rock aquifers (chiefly schist of the Wissahickon Formation) of the Piedmont. Ground water is present under confined and unconfined conditions. The principal...
Chufa biology and management
Leigh H. Fredrickson, James R. Kelley Jr.
1991, Fish and Wildlife Leaflet 13.4.18
Chufa (Cyperus esculentus) is an emergent perennial sedge that is common in seasonally flooded wetlands. Although chufa is common in many States, it is most abundant in the Southeast, including the Mississippi alluvial valley (Fig. 1). Belowground biomass of chufa, especially the tubers, serves as a valuable food source for...
Long-term decline in freshwater mussels (Bivalvia: Unionidae) of the western basin of Lake Erie
Thomas F. Nalepa, Bruce A. Manny, James C. Roth, Samuel C. Mozley, Donald W. Schloesser
1991, Journal of Great Lakes Research (17) 214-219
Long-term trends in the abundance of unionids in the western basin of Lake Erie were examined from data collected at 17 stations in 1961, 1972, and 1982. The mean number of unionids at these stations declined over this time period, decreasing from 10 m−2 in 1961, to 6 m−2 in...
Global climate change: USFWS coastal research
Janet R. Keough, Thomas W. Doyle, Robert E. Stewart Jr.
1991, Conference Paper, Coastal zone '91 : Proceedings of the seventh symposium on coastal and ocean management
Scenarios of global climate change are still ambiguous; however, increasing sea level and atmospheric carbon dioxide (CO2) concentrations seem certain, although rates of change are still being debated. Predictions for other aspects of climate change, such as temperature, tropical storm frequency and intensity, and precipitation, are still in debate, and...
Remote sensing of water quality
Elijah Ramsey III, John R. Jensen
1991, Conference Paper, 1991 ACSM-ASPRS Annual Convention, Baltimore, MD, Mar. 25-29, 1991, Technical Papers. Vol. 3 - Remote Sensing
Water property data were collected within 3 cooling water reservoirs (active to inactive, large [1,068 ha] to small [68.6 ha]. oligotrophic to eutrophic) at 31 locations. A description of the water characteristics was obtained including algal pigments, total suspended particles, dissolved and particulate organic matter, and total particle absorption spectra....
Seasonal changes in microhabitat selection by rainbow trout in a small stream
Donald M. Baltz, Bruce C. Vondracek, Larry R. Brown, Peter B. Moyle
1991, Transactions of the American Fisheries Society (120) 166-176
Shifts in microhabitat selection by rainbow trout Oncorhynchus mykiss were related to seasonal and ontogenetic factors in a small stream characterized by short riffles, small pools, and boulder substrate. Resource availability did not differ significantly between summer and November sampling dates for most variables related to water velocity, substrate, and cover, although...
Evaluation of wetland development and waterbird response at Elk Creek Wildlife management area, Lake Mills, Iowa, 1961 to 1990
M.W. Weller, G.W. Kaufmann, P.A. Vohs
1991, Wetlands (11) 245-262
A waterfowl habitat development project along 7.5 miles (12.07 km) of stream was evaluated after 27 years. There was a modest 12% net increase in wetlands in impounded areas, but much of the wetland vegetation changed from seasonally flooded, nonpersistent and persistent emergents to shallow, open-water areas. An unimpounded, downstream reference area...
The distribution of seabirds and fish in relation to ocean currents in the southeastern Chukchi Sea
John F. Piatt, John L. Wells, Andrea MacCharles, Brian S. Fadely
W.A. Montevecchi, A.J. Gaston, editor(s)
1991, Conference Paper, Studies of high-latitude seabirds. 1. Behavioural, energetic, and oceanographic aspects of seabird feeding ecology (Occasional Paper 68 of the Canadian Wildlife Service)
In late August 1988, we studied the distribution of seabirds in the southeastern Chukchi Sea, particularly in waters near a major seabird colony at Cape Thompson. Foraging areas were characterized using hydrographic data obtained from hydroacoustic surveys for fish. Murres (Uria spp.) and Black-legged Kitttiwakes Rissa tridactyla breeding at Cape Thompson...
Sensitivity of greenback cutthroat trout to acidic pH and elevated aluminum
D. F. Woodward, Aida M. Farag, E. E. Little, B. L. Steadman, R. Yancik
1991, Transactions of the American Fisheries Society (120) 34-42
The greenback cutthroat trout Oncorhynchus clarki stomias is a threatened subspecies native to the upper South Platte and Arkansas rivers between Denver and Fort Collins, Colorado, an area also susceptible to acid deposition. In laboratory studies, we exposed this subspecies to nominal pHs of 4.5–6.5 and to nominal aluminum concentrations of 0,...
Geochemical evolution of acidic ground water at a reclaimed surface coal mine in western Pennsylvania
Charles A. Cravotta III,
1991, Conference Paper, Proceedings American Society of Mining and Reclamation, 1991
Concentrations of dissolved sulfate and acidity in ground water increase downflow in mine spoil and underlying bedrock at a reclaimed surface coal mine in the bituminous field of western Pennsylvania. Elevated dissolved sulfate and negligible oxygen in ground water from bedrock about 100 feet below the water table suggest that...
Impact of exploratory wells, offshore Florida: A biological assessment
Phillip A. Dustan, Barbara H. Lidz, Eugene A. Shinn
1991, Bulletin of Marine Science (48) 94-124
Seven offshore exploratory oil well sites were examined in an effort to determine the ecological impact of exploratory drilling on the subtropical marine ecosystems of southern Florida, including seagrass beds and coral reefs. The time since drilling ranged from 2 to 29 years; water depths varied between 5 and 70...
Oxygen-isotope exchange and mineral alteration in gabbros of the Lower Layered Series, Kap Edvard Holm Complex, East Greenland
Kristen L. Fehlhaber, Dennis K. Bird
1991, Geology (19) 819-822
Multiple intrusions of gabbros, mafic dikes, and syenites in the Kap Edvard Holm Complex gave rise to prolonged circulation of meteoric hydrothermal solutions and extreme isotope exchange and mineral alteration in the 3600-m-thick Lower Layered Series gabbros. In the Lower Layered Series, δ18O of plagioclase varies from +0.3‰ to -5.8‰,...
Wave processes and geologic responses on the floor of the Yellow Sea
James S. Booth, William J. Winters
1991, Book chapter, From shoreline to abyss: Contributions in marine geology in honor of Francis Parker Shepard
The floor of the Yellow Sea is a geologically mundane surface: it is nearly horizontal, lacks relief, and, with few exceptions, is devoid of conspicuous geomorphologic features. However, it is the principal repository for the prodigious sediment load of the Huanghe (Yellow River); and, due to its inherent shallowness (average...
Transient eddy formation around headlands
Richard P. Signell, W. Rockwell Geyer
1991, Journal of Geophysical Research (96) 2561-2575
Eddies with length scales of 1-10 km are commonly observed in coastal waters and play an important role in the...
Numerical simulations of hydrothermal circulation resulting from basalt intrusions in a buried spreading center
A.T. Fisher, T.N. Narasimhan
1991, Earth and Planetary Science Letters (103) 100-115
A two-dimensional, one by two-kilometer section through the seafloor was simulated with a numerical model to investigate coupled fluid and heat flow resulting from basalt intrusions in a buried spreading center. Boundary and initial conditions and physical properties of both sediments and basalt were constrained by field surveys and drilling...
Organic matter and containment of uranium and fissiogenic isotopes at the Oklo natural reactors
B. Nagy, F. Gauthier-Lafaye, P. Holliger, D.W. Davis, D.J. Mossman, J.S. Leventhal, M.J. Rigali, J. Parnell
1991, Nature (354) 472-475
Some of the Precambrian natural fission reactors at Oklo in Gabon contain abundant organic matter1,2, part of which was liquefied at the time of criticality and subsequently converted to a graphitic solid3,4. The liquid organic matter helps to reduce U(VI) to U(IV) from aqueous solutions, resulting in the precipitation of...